Oil-free linear compressor

Abstract

The oil-free linear compressor comprises a shell, a linear driving mechanism, a compression assembly, a supporting mechanism and an exhaust assembly, the linear driving mechanism is used for providing driving force for the compression assembly, and the compression assembly comprises an air cylinder and a piston in clearance fit with the air cylinder; a valve plate assembly is arranged at the end of the piston, a compression cavity is formed between the valve plate assembly and the other end of the air cylinder, static pressure air holes distributed in the axial direction are formed in the side wall of the piston, and a plurality of confluence grooves communicated with the sealing gap are formed in the side wall of the air cylinder; the supporting mechanism is arranged between the piston and the shell; the exhaust assembly comprises a sealing cover connected with the air cylinder in a sealed mode, an exhaust valve is connected into the sealing cover, a high-pressure cover communicated with the sealing cover is arranged at the other end of the sealing cover, and the high-pressure cover is provided with an exhaust pipe communicated with the outside and the interior of the high-pressure cover. Air film sealing is formed through the static pressure air holes, friction loss is remarkably reduced, the service life of parts is prolonged, efficient and sealed exhaust is achieved, and energy loss and leakage risks are reduced.

Description

Technical Field

[0001] This invention relates to the field of compressor technology, and more particularly to an oil-free linear compressor. Background Technology

[0002] A linear compressor is a device that uses a linear motor to directly drive a piston in reciprocating linear motion to compress gas. Compared with traditional rotary compressors that use a crank-connecting rod mechanism, linear compressors eliminate the mechanical structure that converts rotary motion into linear motion. They have advantages such as simple structure, high mechanical efficiency, and easy matching with varying operating conditions. Therefore, they show broad application prospects in refrigeration, air compression, and medical, laboratory, and food industries that require high-purity gases.

[0003] However, existing linear compressors, especially in achieving oil-free lubrication, still face many challenges.

[0004] Traditional compressors typically use lubricating oil to achieve lubrication and sealing between the piston and cylinder. However, the presence of lubricating oil contaminates the compressed medium (such as refrigerant, air, or special process gases), making it unsuitable for applications requiring extremely high gas purity. Although the concept of oil-free compressors has been proposed, a core technical challenge remains: how to ensure effective sealing to prevent high-pressure gas leakage while minimizing friction and wear between the piston and cylinder without using lubricating oil. Simple gap seals suffer from severe leakage and low efficiency under high pressure; while dry contact seals lead to rapid wear, poor reliability, and short lifespan.

[0005] In an oil-free environment, the piston is prone to deflection due to lateral forces during high-speed reciprocating motion, resulting in dry friction with the cylinder wall and causing malfunctions such as cylinder scoring or seizure. Some existing support structures may be complex or fail to provide continuous and stable radial support, affecting the smoothness and reliability of compressor operation.

[0006] The performance of the linear drive mechanism directly affects the compressor's energy efficiency and vibration and noise levels. If the magnetic circuit design is unreasonable or the coordination between the mover and stator is poor, it may lead to large fluctuations in driving force, low efficiency, and even significant vibration and noise.

[0007] In addition, the exhaust valve is a key component affecting the compressor's volumetric efficiency and energy loss. Traditional valve designs, if unresponsive or poorly sealed, can cause gas backflow, increased pressure loss, and generate additional noise and heat, thereby reducing overall machine efficiency.

[0008] To address these issues, the industry has explored various approaches. For instance, some technologies have attempted to create vents on the piston, utilizing the compressed gas itself to form a gas film for non-contact "gas lubrication." However, such designs often suffer from uneven gas film distribution, poor dynamic stability, and a sharp decline in sealing performance under varying operating conditions. Without optimization of the airflow channels and pressure distribution within the cylinder, the piston cannot be effectively balanced, and leakage under high pressure remains significant. Summary of the Invention

[0009] The purpose of this invention is to provide an oil-free linear compressor to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention employs the following technical means: An oil-free linear compressor includes a housing, a linear drive mechanism, a compression assembly, a support mechanism, and an exhaust assembly, wherein: The linear drive mechanism is used to provide driving force for the compression assembly, and includes a stator and a mover. The stator is fixed to the inner wall of the housing, and the mover is rigidly connected to the compression assembly. The mover reciprocates relative to the stator. The compression assembly, used to compress the medium, includes a cylinder and a piston that is inserted into one end of the cylinder under the drive of the mover and reciprocates linearly along the cylinder axis and is in clearance fit with the cylinder. A valve plate assembly is provided at the end of the piston to form a compression chamber between the piston and the other end of the cylinder. A sealing gap with communication is formed between the piston and the cylinder. The side wall of the piston is provided with static pressure air holes evenly distributed along its axial direction, and the side wall of the cylinder is provided with a number of manifolds communicating with the sealing gap. The support mechanism is used to elastically support and is disposed between the piston and the housing; The exhaust assembly includes a sealing cover that is sealed to the cylinder. An exhaust valve on the end face of the cylinder is connected to the sealing cover by a spring. The other end of the sealing cover is provided with a high-pressure cover that communicates with the sealing cover. The high-pressure cover is provided with an exhaust pipe that communicates with the outside and the inside of the high-pressure cover.

[0011] In some embodiments, the linear drive mechanism further includes an inner magnetic pole disposed on the outer wall of the cylinder, and there is a gap between the inner magnetic pole and the mover.

[0012] In some embodiments, the cylinder is a hollow cylindrical structure, and one end of the cylinder has an annular groove that cooperates with the exhaust valve in the exhaust assembly.

[0013] In some embodiments, four sets of uniformly arranged static pressure air holes are respectively provided at both ends of the piston, and four sets of uniformly distributed confluence grooves communicating with the sealing gap are provided inside the side wall of the cylinder.

[0014] In some embodiments, the static pressure air hole includes a first part and a second part that are arranged from the inside to the outside on the side wall of the cylinder and connected in sequence, with the central axis perpendicular to the center line of the cylinder. The inner diameter of the first part is smaller than the inner diameter of the second part.

[0015] In some embodiments, the manifold includes a first axial groove, a second axial groove, and a first radial groove. The first axial groove is disposed on the inner wall of the cylinder and is perpendicular to the center line of the cylinder and extends toward the inner wall of the cylinder. The second axial groove is disposed on the inner wall of the cylinder and is perpendicular to the center line of the cylinder and extends toward the inner wall of the cylinder. The first radial groove extends radially from one end of the inner wall of the cylinder and connects the first axial groove and the second axial groove.

[0016] In some embodiments, the cylinder includes a hollow cylinder with a sealed end, an L-shaped structural member surrounding the bottom sidewall of the hollow cylinder, a mounting post cooperating with a support mechanism on the inner wall of the sealed end of the hollow cylinder, and at least one set of valve holes opened at the sealed end of the hollow cylinder, wherein the central axis of the valve holes is not on the same straight line as the center line of the hollow cylinder.

[0017] In some embodiments, the support mechanism is a rigid spring.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes a static pressure vent to form a gas film seal, eliminating the need for lubrication and ensuring the purity of the compressed medium. A clearance fit is used between the piston and cylinder, and gas is introduced through the static pressure vent to form a gas film, achieving contactless movement, significantly reducing friction loss, and extending component life. The linear drive mechanism directly drives the compression assembly, reducing energy conversion steps, improving response speed and control precision, thereby enhancing overall energy efficiency. The support mechanism elastically supports the piston and housing, effectively absorbing vibration, preventing piston misalignment, and ensuring smooth operation. The exhaust assembly, through a spring-connected exhaust valve and high-pressure cover design, achieves efficient and sealed exhaust, reducing energy loss and leakage risks. Attached Figure Description

[0019] Figure 1 These are schematic diagrams illustrating the structure according to some embodiments of this specification; Figure 2 These are schematic diagrams illustrating the structure according to some embodiments of this specification; Figure 3 These are schematic diagrams illustrating the structure according to some embodiments of this specification; Figure 4These are schematic diagrams illustrating the structure according to some embodiments of this specification. Detailed Implementation

[0020] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. The following embodiments and drawings are only used to more clearly illustrate the technical solution of this application, and are therefore merely examples and should not be used to limit the scope of protection of this application. The drawings only schematically show the parts related to the technical solution of this application, and do not represent their actual structure as a product.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0022] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0025] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0026] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0027] In this embodiment, an oil-free linear compressor includes a housing 100, a linear drive mechanism 200, a compression assembly 300, a support mechanism 400, and an exhaust assembly 500, wherein: The linear drive mechanism 200 is used to provide driving force for the compression assembly 300. It includes a stator 210 and a mover 220. The stator 210 is fixed to the inner wall of the housing 100. The mover 220 is rigidly connected to the compression assembly 300. The mover 220 reciprocates relative to the stator 210. The compression assembly 300, used to compress the medium, includes a cylinder 310 and a piston 320 that is inserted into one end of the cylinder 310 under the drive of the mover 220 and reciprocates linearly along the axis of the cylinder 310 and is in clearance fit with the cylinder 310. A valve plate assembly is provided at the end of the piston 320 to form a compression chamber 330 between the piston 320 and the other end of the cylinder 310. A sealing gap 340 with communication is formed between the piston 320 and the cylinder 310. The side wall of the piston 320 is provided with static pressure air holes 350 evenly distributed along its axial direction, and the side wall of the cylinder 310 is provided with a plurality of manifolds 360 communicating with the sealing gap 340. The support mechanism 400 is used to elastically support and is disposed between the piston 320 and the housing 100; The exhaust assembly 500 includes a sealing cover 510 that is sealed to the cylinder 310. An exhaust valve 520 is connected to the end face of the cylinder 310 via a spring inside the sealing cover 510. A high-pressure cover 530 communicating with the sealing cover 510 is provided at the other end of the sealing cover 510. The high-pressure cover 530 has an exhaust pipe 540 connecting the outside to the interior of the high-pressure cover 530. In the above embodiment, direct reciprocating drive is provided by the linear drive mechanism 200, resulting in a simple structure and high efficiency. In the above embodiments, the clearance between the piston 320 and the cylinder 310 in the compression assembly 300, combined with the axially uniformly distributed static pressure air holes 350 on the side wall of the piston 320 and the manifold 360 on the inner wall of the cylinder 310, allows the high-pressure medium in the compression chamber 330 to form a uniform static pressure air film through the static pressure air holes 350 and the manifold 360. This suspends and supports the piston 320 within the cylinder 310, significantly reducing direct friction between the piston 320 and the cylinder 310, lowering motion resistance, and improving compressor efficiency. Simultaneously, it avoids mechanical wear, extending the service life of the piston 320 and the cylinder 310. The combination of the static pressure air holes 350 and the manifold 360 effectively forms air film lubrication and sealing, achieving oil-free operation, promoting uniform gas distribution, and enhancing the sealing effect. In the above embodiments, the support mechanism 400 provides elastic support, reducing vibration and noise, improving operational stability, and compensating for dimensional changes caused by assembly errors or thermal expansion, preventing component jamming. In the above embodiments, the exhaust assembly 500 achieves unidirectional stable discharge of high-pressure medium, the spring-driven exhaust valve 520 automatically adapts to the pressure changes of the compression chamber 330, the exhaust response is rapid, it can automatically adjust, prevent backflow, and improve compression efficiency. The sealing cover 510 and the high-pressure cover 530 are sealed together to ensure that there is no leakage of high-pressure medium and improve compression efficiency.

[0028] In some embodiments, the linear drive mechanism 200 further includes an inner magnetic pole 230, which is disposed on the outer wall of the cylinder 310, and a gap exists between the inner magnetic pole 230 and the mover 220. In the above embodiments, the inner magnetic pole 230 can enhance the magnetic field strength and distribution uniformity, improve the electromagnetic conversion efficiency of the linear drive mechanism 200, reduce magnetic field leakage, reduce energy consumption, and at the same time make the mover 220 more uniformly stressed and more accurate in reciprocating motion, thereby improving the uniformity and efficiency of the driving force. The gap between the inner magnetic pole 230 and the mover 220 avoids mechanical contact, reduces wear, and further improves the smoothness of operation and service life. In some embodiments, referring to the accompanying drawings, the stator 210 includes an outer magnetic pole and a coil arranged inside the outer magnetic pole. The outer magnetic pole and the inner magnetic pole 230 together form a radial magnetic circuit. The mover 220 is disposed in the air gap between the inner magnetic pole 230 and the outer magnetic pole, which can significantly enhance the magnetic flux density of the air gap, improve the thrust density and efficiency of the linear drive mechanism 200, and enable the compressor to output greater power in the same volume, or achieve a smaller size in the same power. In some embodiments, the linear drive mechanism 200 generates heat during high-speed reciprocating motion, affecting the performance of the magnet and the life of the device. Based on this, the mover 220 is a hollow cylindrical structure with vent holes at both ends, allowing some of the intake medium to flow through the interior of the mover 220 for cooling. In some other embodiments, the housing 100 is provided with a cooling channel surrounding the stator 210. The cooling channel has a cooling medium inlet and an outlet communicating with the outside, using the low-temperature medium drawn in by the compressor itself or an independent coolant to forcibly cool the motor, ensuring stable operation of the compressor under high temperature or high load conditions.

[0029] In some embodiments, the cylinder 310 is a hollow cylindrical structure, and one end of the cylinder 310 has an annular groove 311 that cooperates with the exhaust valve 520 in the exhaust assembly 500. In the above embodiments, the annular groove 311 cooperates with the exhaust valve 520 to provide a clear installation reference and limiting structure for the exhaust valve 520, ensuring a tight fit between the exhaust valve 520 and the end face of the cylinder 310 to prevent gas leakage. The annular groove 311 can guide the flow direction of the medium after the exhaust valve 520 is opened, reduce exhaust resistance, improve exhaust efficiency, and at the same time avoid the generation of eddies in the medium near the exhaust port, reducing flow noise.

[0030] In some embodiments, four sets of uniformly arranged static pressure air holes 350 are respectively provided at both ends of the piston 320, and four sets of uniformly distributed manifolds 360 communicating with the sealing gap 340 are provided inside the side wall of the cylinder 310. In the above embodiments, the uniform distribution of the static pressure air holes 350 and manifolds 360 ensures that the air film is uniformly formed around the piston 320, avoiding wear or jamming caused by uneven local pressure, so that the high pressure medium forms a 360° uniformly distributed static pressure air film in the sealing gap 340 between the piston 320 and the cylinder 310, avoiding uneven wear or tilting of the piston 320 due to uneven force, further reducing friction loss, improving the coaxiality of the reciprocating motion of the piston 320, ensuring the accuracy of the volume change of the compression chamber 330, thereby improving the pressure stability of the compressed medium, improving sealing and smoothness of movement.

[0031] In some embodiments, the static pressure air port 350 includes a first part 351 and a second part 352 arranged sequentially from the inside to the outside on the side wall of the cylinder 310, with their central axes perpendicular to the center line of the cylinder 310. The inner diameter of the first part 351 is smaller than the inner diameter of the second part 352. In the above embodiments, the stepped arrangement of the first part 351 and the second part 352 can control the gas flow speed and pressure. The smaller inner diameter of the first part 351 generates a higher airflow speed, while the larger inner diameter of the second part 352 diffuses the airflow, forming a more stable gas film and improving lubrication and sealing performance.

[0032] In some embodiments, the manifold 360 includes a first axial groove 361, a second axial groove 362, and a first radial groove 363. The first axial groove 361 is disposed on the inner wall of the cylinder 310 and is perpendicular to the center line of the cylinder 310 and extends toward the inner wall of the cylinder 310. The second axial groove 362 is disposed on the inner wall of the cylinder 310 and is perpendicular to the center line of the cylinder 310 and extends toward the inner wall of the cylinder 310. The first radial groove 363 extends radially from one end of the inner wall of the cylinder 310 and connects the first axial groove 361 and the second axial groove 362. In the above embodiment, the first axial groove 361 and the second axial groove 362 extend axially along the inner wall of the cylinder 310, and together with the radially connected first radial groove 363, form a three-dimensional flow network, which can quickly deliver the high-pressure medium to various areas of the inner wall of the cylinder 310, ensuring that the gas film pressure at each position in the sealing gap 340 is uniform. At the same time, the first radial groove 363 can balance the pressure difference between the axial grooves, avoid local gas film being too thin or ruptured, ensure that the gas is distributed quickly and evenly, reduce flow resistance, and improve compression efficiency and gas film stability.

[0033] In some embodiments, the cylinder 310 includes a hollow cylinder 301 with a sealed end. The bottom sidewall of the hollow cylinder 301 is surrounded by an L-shaped structural member 312. The inner wall of the sealed end of the hollow cylinder 301 is provided with a mounting post 313 that cooperates with the support mechanism 400. The sealed end of the hollow cylinder 301 has at least one set of valve holes 314. The central axis of the valve holes 314 is not on the same straight line as the center line of the hollow cylinder 301. In the above embodiments, the hollow cylinder 301 and the L-shaped structural component 312 are integrally formed, which can strengthen the structure of the cylinder 310. The sealing end of the hollow cylinder 301 can directly form one end wall of the compression chamber 330, reducing the use of additional sealing components and reducing the risk of leakage. The mounting column 313 provides a precise installation position for the support mechanism 400, ensuring that the force direction of the support mechanism 400 is consistent with the movement direction of the piston 320, thus improving the buffering effect. The central axis of the valve hole 314 is not on the same straight line as the center line of the cylinder 310, which can avoid interference between the valve plate and the end of the piston 320 or the internal structure of the compression chamber 330 when the valve plate moves, ensuring that the valve plate can open and close flexibly. At the same time, at least one set of valve holes 314 can increase the exhaust flow area, reduce exhaust resistance, and increase the exhaust volume and working efficiency of the compressor. Moreover, the offset setting of the valve holes 314 can improve airflow dynamics, reduce eddy current losses, and improve compression efficiency and exhaust uniformity. In some embodiments, three sets of valve holes 314 are provided. In some embodiments, four sets of valve holes 314 are provided.

[0034] In some embodiments, the support mechanism 400 is a rigid spring. In the above embodiments, the rigid spring provides stable elastic support, has high rigidity, effectively limits the radial movement of the piston 320, prevents deflection, and absorbs the impact of reciprocating motion, thereby improving durability and operational accuracy.

[0035] In some embodiments, the inner wall of the cylinder 310 is provided with an axially arranged striped structure 370. In the above embodiments, the striped structure 370 is an axially extending micro-groove or ridge, which is equivalent to adding several axial auxiliary flow channels to the inner wall of the cylinder 310. This allows the high-pressure medium entering the sealing gap 340 through the static pressure air hole 350 and the confluence groove 360 ​​to diffuse rapidly and uniformly along the axial direction to the entire length of the cylinder 310, avoiding insufficient local air film pressure or rupture due to poor medium flow. The axially extending striped structure 370 does not obstruct the flow of medium in the reciprocating motion direction of the piston 320, and at the same time can break the area in the sealing gap 340 where the medium cannot flow, ensuring that a static pressure air film of uniform thickness can be formed throughout the entire stroke of the piston 320, further improving the stability of the piston 320 suspension support, and effectively meeting the core requirement of oil-free lubrication. For trace impurities that may be present in the compressed medium, such as dust and particles, the striped structure 370 can accommodate them, preventing impurities from accumulating in the sealing gap 340 and scratching the inner wall of the piston 320 or cylinder 310, thus improving the operational reliability of the compressor in complex media environments. The striped structure 370 increases the surface area of ​​the inner wall of the cylinder 310, which helps to conduct the heat generated during compression to the outside through the cylinder 310 wall, reducing the temperature in the sealing gap 340 and avoiding changes in the properties of the medium or thermal deformation of components caused by high temperatures, further ensuring the long-term stable operation of the compressor. When the piston 320 reciprocates, the axial groove formed by the striped structure 370 can serve as an auxiliary exhaust channel, quickly discharging the low-pressure medium remaining in the sealing gap 340 to the manifold 360 or exhaust assembly 500, reducing compression losses caused by medium retention and improving compression efficiency.

[0036] The specific embodiments disclosed in this invention fall within the scope of protection of the claims of this invention, and are specific subordinate implementations of the characteristic parts of this invention. The protection content of the specific embodiments is merely an explanation of the scope of protection of the claims of this invention, and the scope of protection of this invention is not limited to the protection content of the specific embodiments. The protection content of the specific embodiments should not be construed as a limitation on the scope of protection of the claims of this invention. All product structural connection relationships falling within the scope of protection of this invention are also within the scope of protection of this invention. Conventional technical improvements to the structure of product components without departing from the essence of protection of this invention, such as the improvements to the structure of some parts of the product as described in the specific embodiments of this invention, will also fall within the essence of protection of this invention.

Claims

1. An oil-free linear compressor characterized by: The shell, linear drive mechanism, compression assembly, support mechanism and exhaust assembly are provided. The linear drive mechanism is used for providing driving force for the compression assembly and comprises a stator and a mover. The compression assembly is used for compressing medium and comprises a cylinder and a piston inserted into one end of the cylinder and moving along the cylinder axis under the driving of the mover. The support mechanism is arranged between the piston and the shell. The exhaust assembly comprises a sealing cover connected with the cylinder, a spring, an exhaust valve on the end surface of the cylinder, a high-pressure cover connected with the sealing cover, and an exhaust pipe connected with the outside and the inside of the high-pressure cover.

2. An oil-free linear compressor according to claim 1, characterized in that: The linear drive mechanism further comprises an inner magnetic pole arranged on the outer wall of the cylinder.

3. An oil-free linear compressor according to claim 1, characterized in that: The cylinder is a hollow cylindrical structure, and one end of the cylinder is provided with an annular groove matched with the exhaust valve of the exhaust assembly.

4. An oil-free linear compressor according to claim 1, characterized in that: The two ends of the piston are respectively provided with four groups of static pressure gas holes arranged uniformly.

5. An oil-free linear compressor according to claim 4, characterized in that: The static pressure gas hole comprises a first part and a second part arranged on the side wall of the cylinder from inside to outside and sequentially connected, and the central axis of the first part is perpendicular to the center line of the cylinder.

6. An oil-free linear compressor according to claim 1, characterized in that: The flow collection groove comprises a first axial groove, a second axial groove and a first radial groove.

7. An oil-free linear compressor according to claim 1, characterized in that: The cylinder comprises a hollow cylinder arranged at one end, and the bottom side wall of the hollow cylinder is surrounded by an L-shaped structure.

8. An oil-free linear compressor according to claim 1, characterized in that: The support mechanism is a rigid spring.

9. An oil-free linear compressor according to claim 1, characterized in that: The inner wall of the cylinder is provided with an axial stripe structure.

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